The present invention relates to a system for computer-assisted organization of workpieces to be processed, as well as to a corresponding method of organization.
In a production process, workpieces are subjected to different processings, which are carried out by a plurality of different tools. For example, in the production of an injection mold in the tool room, starting from a blank the workpiece in question is bored, milled, wire-cut and ground, polished, and the like. In this, the workpiece in question is usually situated on a workpiece carrier, especially on a so-called “pallet”, that serves as a base for the clamping of the workpiece into the processing devices. The pressure of productivity leads to the fact that the cycle times of workpieces must be ever shorter and the utilization of the machines improved. In addition, errors in the production process, for example due to an incorrect occupying of a magazine position by the operator, a necessary reworking of the workpiece, or through false information of the controls, should be avoided. All of this causes considerable delays in the production process. If organizational changes in the production process become necessary, it must be possible to react to such changes quickly.
Known from US 2003/0055525 A1 is a system as well as a method for production of plastic injection-mold components. This known system comprises a number of so-called subcells, in each of which a number of workpieces are held ready and are processed, as well as a superordinated master cell with a central control unit as well as a central robot for feeding the workpieces stored in the master cell to the individual subcells. Each individual pallet is provided with an ID, for example in the form of a computer chip, a barcode, or an optical code. The IDs ensure that the master robot can identify the workpieces in question with the aid of the ID of the pallet and thereby join the correct workpiece, for example an injection mold or an electrode, with the correct carrier intended for it. Typically, extraction robots have a reader on their grasping arms. However, this is associated with very long identification times. During this time, the robot cannot load or unload any machine. If an operator looks at the magazine, he perceives only free as well as occupied workpiece positions. However, the operator cannot perceive which workpiece position is actually free (as opposed to a workpiece position that is only temporarily occupied, since the workpiece is being processed in the machine just then). This represents a source of uncertainty that negatively affects the process.
Described in the offprint from Werkzeug und Formenbau 5, 05, published by MI Verlag moderne Industrie, is the Winstat MES system, in which each pallet, i.e. each electrode holder, possesses a contact-free identification system in the forms of a transponder. At the start of the processing, the workpiece is mounted in the pallet as a blank and the ID of the pallet is registered in the system via a portable PC. Then, depending on the imported ID, the processing programs needed for the planned processing can be called up by the system. Common to the aforementioned prior art is the fact that although pallets are already identified by the system, nevertheless the selection or assignment of pallets to workpiece positions still takes place in operation by the operator, so to speak by hand, or, based on the central data-processing unit, a selection of the relevant workpiece type as such takes place.